Reduction of NO{sub x} emissions from a dry process preheater kiln with calciner through the use of the urea-based SNCR process

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · IEEE Transactions on Industry Applications

DOI:https://doi.org/10.1109/28.511629· OSTI ID:372147

Steuch, H E ^[1]; Hille, J T ^[2]; Sun, W H ^[3]; Bisnett, M J; Kirk, D W ^[4]

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1. Ash Grove Cement Co., Portland, OR (United States)
2. Ash Grove Cement Co., Seattle, WA (United States)
3. Nalco Fuel Tech, Naperville, IL (United States)
4. Nalco Fuel Tech, Santa Fe Springs, CA (United States)

The post combustion reduction of NO{sub x} using urea has proven to be an effective method in controlling NO{sub x} from various combustion sources. Such a reduction process has been successfully demonstrated in a week-long test at Ash Grove`s dry process cement kiln system located in Seattle. This system is equipped with planetary coolers, a 5-stage preheater and an air-through-the-kiln calciner. Testing was done under ten different kiln/calciner operating conditions. Using three to four injectors, NO{sub x} was efficiently reduced from 350--600 lb per hour lb/ton of clinker to less than 100 lb per hour. This calculates to a NO{sub x} reduction of greater than 80% for most cases. Chemical utilization was greater than 50%. A high degree of mixing and a long residence time at an appropriate temperature present in the preheater tower contributed to these excellent results. An average ammonia slip was four ppm above a baseline level at a normalized stoichiometric ratio of 1. This demonstration confirms expectations that dry process cement kilns with 4+ preheater stages are an ideal application for the selective noncatalytic reduction of NO{sub x} with urea. NO{sub x} was efficiently and effectively reduced with minimal byproduct emissions and virtually no effect on plant operations.

• OSTI ID: 372147
• Journal Information: IEEE Transactions on Industry Applications, Journal Name: IEEE Transactions on Industry Applications Journal Issue: 4 Vol. 32; ISSN 0093-9994; ISSN ITIACR
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
AIR POLLUTION CONTROL
CEMENT INDUSTRY
KILNS
NITROGEN OXIDES
REDUCTION